The Islamic State (IS) group beheaded Thursday a Syrian imam, or mosque prayer leader, for "insulting God," a monitoring group said.
"The IS executed the imam of a mosque from the village of Abu Khuyut near Hasakeh city (in northeastern Syria) at dawn Thursday," said the Syrian Observatory for Human Rights.
The Britain-based Observatory added that three of the mans's sons were IS fighters, and that it was the first time the jihadists executed a religious official for this reason.
The man was detained after watching a video on executions carried out by IS and cursing because God had permitted them, Observatory director Rami Abdel Rahman said.
The IS carries out near-daily executions in the territories of Syria and Iraq that it controls.
Originating in Iraq, it appeared in Syria's civil war in spring 2013, and has since committed some of the conflict's worst abuses.